Electric apparatus



'Mar- 95 1927" P. c. HEWITT ELECTRIC APPARATUS Filed J ly 30, 1920 2 Shqets-Sheet l His ATTORNEY Aug. 9, 1927. 1,638,158

P. c. HEWITT.

ELECTRIC APPARATUS Filed Juli; so. 1920 I a sneeza-snbet 2 Patented Aug. 9, 1927.

UNITED STATES 1,638,158 PATENT OFFICE.

PETER COOPER HEWITT, F RINGWOOD MANOR, NEW JERSEY; THE FARMERS AND TRUST COMPANY. EXECUTOR OE SAID PETER COOPER HEWITT, DECEASED, A- SIGNOR TO COOPER HEWITT ELECTRIC COMPANY, OF HOBOKEN, NEW mm, A

CORPORATION OF NEW JERSEY.

nmcrmo APPARATIIS.

Application ma Jul so, 1920. serial no. 400,292.

The object of this invention is to provide very sensitive means for receiving minute electrical variations and consists in'the control of the reactions affecting the conducting 5 condition of the space between two electrodes in an evacuated vessel.

My invention consists of an evacuated vessel exhausted to a vacuum sufficiently high .to obtain the results desired and in case of their use for receiving wireless messages when exhausted to a high vacuum a differ: ence of potential may be applied between the positive terminal and the filament acting as the negative of the work circuit or output circuit. Apparently, the higher this potential difference is made. the greater the. variation will be in the output circuit. for the same signal. In other words, the greater the difference of potential between the positive terminal of.the receiving circuit and the negative, the greater the sensitiveness of the device. within comparatively wide limits, and under certain conditions. although low resistance devices of this principle are very sensitive. The size of the positive terminal and its surface area bear a direct relation to this difference of potential and the larger the positive the lower its resistance other things being equal. The size of the filament,

which is the negative electrode terminal and its area affect this difference of potential as well as the temperature at which its is operated.

By making the positive large and the filament small, a larger proportion of the resistanqe to the passage of the current can be had at the negative terminal.

By making the positive relatively small as to its surface and size and the negative filament relatively large, the larger proportlon of resistance may be had at the positive terminal. These relations are important for specific uses, as they enable the control of the reactions or resistance phenomena occurring at orabout either the positive or the negative terminal and the reaction at either may be so made available for use when 1n close proximity to the eifect of a charge acting on the device. This enables the use of the specific characteristics of each occur ring within the device.

These reactions are sensitive invarying degrees to potential variations afiecting them and such potential variations may be caused to affect the reactions by an independent charged conductor or conductors properly located within the device and the charge may be made definite in direction by a potential difference applied between one conductor and another. The conductor or conductors used for applying a charge may be called potential terminal or terminals and have for their function the creation of a state of electrical stress in a definite direction and location within the device. By means of such stress, reactions occurring in the path between the positive and the negative terminals of the work circuit, the action of the device may be modified and controlled.

The reactions manifest at or in close proximity to the positive terminal and at or in.

close pronimity to the negative terminal, and the reactions that may reside between these two sets of reactions, may be afl'ected in such manner by electrical stress that some of them may manifest equal and opposite resistance characteristics. so that although there has been a wide change of the resistance distribution within the device, there will be but slight. change of resistance in the circuit of the device. The purpose of appl ing charges in a definite direction and de nite localities and by properly correlating the size of the negative and positive terminals, is to prevent the annulling of one resistance change by another by-modifying the magnitude of one of these reactions by meansof the relative size of the electrodes, the direction of the charge applied, and the degree of vacuum within the device. These reactions may be so correlated that their tendency is to increase together or decrease together and so by their annulment or b action developed the total resistance mani esta-.

tion may approximate one resistance change or the sum of two or more in the same dlrection; that is, increase or decrease, so that V the total change of resistance over the device may be made to approximate the sumpf the resistance reactions within the device acting in the same way.

I provide a high resistance connection be- CRUSH).

to the other, the device will operate without the high resistance connectionbut is usually not so sensitive nor so stable as with this Ink devices of this character, terminals are apt or may receive charges connection.

from the interior of the device by reason of reactions developed in the device. The high resistance positive connection provides means for utilizing such charges and in a certain measure determining and fixing the electrical relation of each with respect to the other thereby tending to produce uniformity of and the utilization of the internal relations in the device. The high resistance used to connect the potential terminal circuit to the output positive electrode is in order of from 50,000,000 to 500,000,000 ohms.

I prefer to apply theincoming variations by means of a circuit connecting the poten tial terminals and 'prefer that a portion of such circuit be so located that a difference of potential is obtained between two potendiameter tial terminals within the device. This may be done by tuning that particular circuit with reference to the frequency to be received and affecting it by the incoming signal or in case of lower frequency by causing a. secondary of a transformer to give adifference of potential to the potential terminals.

My device is particularly applicable. to very high frequencies such as are used in wireless telegraphy and even higher frequencies and also to low frequencies such as would come within the range of musical notes and even lower frequencies.

In my device the main negative electrode consists of tungsten wire of about -.002 inches an inches in length, and is heated to atemperature required for its operation as a negatrode.

practicall tive. The negative electrode is connected by means of a circuit having a suitable source of current of from twenty to two hundred volts or more to the positive elec- The positive electrode is about .005 inches in diameten and about one inch long and of tungsten and is separated fromthe negative electrode by about five thirty-seconds of an inch. The potential terminals .are of tungsten and about .005 inches in diameter and 'one inch long and separated from each other by about-one-eighth of an inch, and under service conditions, have no electrical leak or power of transmittlng current when acting as a negative, they are capable of producing in the space separating them a stress as if by nature the separation were of a dielectric so substantially five-eighth 7 is that as if they were separated by a dielectric rather than that of a conductor and by means the action on the conductivity of the space and included reactions forming part of the output circuit may be considered to change in conductivity due to dielectric stress brought about by difference of potential at the otential terminals.

One oft ie objects of this invention is to provide a device that will be sensitive to. electrical variations of a very minute order and be sensitive to variations small as compared with those capable of being received by a sensitive crystal ar electrolytic detector, and provide a device which in itself has the quality of inherent silence. In fact, so minute as to be incapable of detection by a sensitive telephone connected in the output circuit of a device, but the currents neverthelessin this circuit being passed through a suitable cascade of amplifiers and multiplied many thousand times make the minute variations eventually recognizable in a translating device.

I have found the advantageous selection of material within the device is very important for suppressing internal physical or chemical action due to the presence of current; any such action is apt to manifest itself in variation in a uniform current passing through the device and may on magnification be perceived by the use of a telephone giving rise to a sense of crackling or hissing noises.

Iv have illustrated my invent on in the accompanying drawings, in which Figure 1 is a diagram of a radio receiving circuit in which my improved device is utilized as a detector in conjunction with an amplifier cascade and translating devices; Figure 2 is a diagram showing an alternative connection for the cascade amplifiers; Figure 3 is a view of a tube having a positive electrode and potential terminals of straight wire and a coiled wire negative electrode. all the terminals and electrodes being parallel and substantially coextensive in the tube; Figure 4 is a section on the line 4 4 of Figure 3; Figure 5 is a view of a tube having all its electrodes and terminals of coiled wire, said\ electrodes and terminals being parallel and substantially coextensive. and extending horizontally across the tube; Figure 6 is a section on the line 66 of Figure 5; and Figure 7 is a diagram of a novel form of electrostatic coupling between a detector and its antenna. v a i A specific form of evacuated device embodyingmy' invention is had in the accompanying drawing and consists of an enclosing vessel 1 made of glass, having suitable leads sealed in through the walls of the vessel ing a tungsten wire, a filament 3 connected aeaaua within the device. A positive terminal 2 betherewith by means of circuit 4 which includes a battery 5 and an inductance 6. The filament 3 has an energizing circuit 7 including resistance 8, battery 9, and circuit 7, for the purpose of maintaining it at the desired temperature. Potential terminals 10 and 11 are located either side of the current path 12 between the positive terminal 2 and the negative terminal 3 of the receiving circuit. These terminals 10 and 11 are connected in and by circuit 13 having included in it an inductance 14. This circuit is connected to the positive electrode 2 by means of a hi h resistance 23, thereb causingthe potentlal terminals to be acte on and form part of the circuit of the positive terminal 2. The inductance 14 is in inductive relation to the inductance 15 by means of which the incoming applied energy to be received is applied, 14 and 15 forming the secondary and primar of a transformer and the circuit of 14 is pre erabl tuned in resonance to the time period 0 the incoming signal. The applied ener y creates variation of potential at the terminals 10 and 11 causing an electric stress between them and the conducting space 12- and bring about variations of the electrical reactions in space 12 as well as at the surface of the terminals 2 and 3, whereby variations of resistance are brought about in circuit 4 causing a variation of current flow and a variation of energy derived from the batter 5 causin variation in the inductance 6 a footing the inductance 16, 6 and 16 being the primary and secondary of a transformer and 16 is included in a circuit 17 which is the output circuit and contains the translatingor receiving device 18 here shown as a telephone. 15 is shown as forming part of an aerial circuit and is the source of input variations. condenser 19, aerial 20 and ground lead 21. The ground lead 21 is connected by means of line 22 to the positive lead 2 of the circuit 4 and may be also connected to the lead from the potential terminal 10 through its circuit 13 by means of the high resistance 23, extending from circuit 13 to circuit 22,

whereby the terminals of all the circuits are ically. Such variations may be applied This circuit comprises variable statically b the use of a coil of shorter time perio! than the time period of the variations desired to be received, by placing on its surface a small surface of conductor, shown at 25. Whenthis conductor 25 is electrfcally connected to the source of electrical variation, the time period of the coil will tion to said electrodes, and a fifty megohm resistance connecting the positive terminal to the potential terminal peculiar to said terminals.

2. An electric device comprising a container, a negative electrode and a positive electrode therein and extending across the container in parallel relation, and a pair of control electrodes substantially coextensive with and parallel to said electrodes and out of the path between said electrodes, and a high resistance connection from the positive electrode to one of said control electrodes.

3. An electric device comprising a container, a negative electrode and a positive electrode therein in parallel relation, and a pair of potential terminals in parallel rela tion in a plane at an angle to the plane of said electrodes and substantially coextensive therewith, a resistance of more than ten,

megohms connecting the positive electrode and a potential terminal.

4. An electric device comprising a container, a negative electrode and a positive electrode therein in parallelrelation, a pair of potential terminals in parallel relation and in a plane at an angle to the plane of said electrodes and substantially coextensive therewith, and a high resistance connection between the positive electrode and a potential terminal.

5. An exhausted container containing positive and negative electrodes and two potential terminals connected by a circuit, said circuit being connected to the positive electrode bymeans of a high resistance peculiar to said positive electrode.

6. An exhausted container containing positive and negative electrodes, and two potential terminals connected by a circuit having inductance of definite time period, said circuit being connected to the positive electrode by means of a high resistance peculiar to said itive electrode.

7 exhausted'container containing positive and negative electrodes and two potential terminals connected by a'circult potential terminal connected b a circuit having included in it a spiral 0 definite-time period, said circuit being connected to the positive electrode bymeansof a high resistance culiar to the positive electrode.

8. l electric circuit and an electronic device connected thereto, the electronic device comprising an envelope ,and electrodes in said envelope and being characterized by the following relationship of said electrodes: a negative electrode of tungsten wire of about 0.002" diameter and substantially five-eighths of an inch in length, a positive electrode of tungsten wire of about 0.005" in diameter and about one inch in length, said negative and positive electrodes being spaced apart five-thirty-seconds of an inch, a pair of supplementary electrodes of tungsten of about 0.005" diameter and about one inch in length and separated from each other about one-eighth of an inch, a lead for each end of said negative electrode and a lead for each of the other of said electrodes.

9. An electric circuit and an electronic device connected thereto, the electronic device comprising an envelope and electrodes in said envelope and being characterized by the following relationship of said electrodes: a negative electrode of tungsten wire of about 0.002"- diameter and substantially fiveeighths of an inch in length, a positive electrode of tungsten wire of about 0.005" in diameter and about one inch in length, said negative and positive electrodes being spaced apart five-thirty-seconds of an inch, a pair of supplementary electrodes of tungsten of about 0.005 diameter and about one inch in length and se arated from each other about one-eighth 0 an inch, a lead for each end of said negative electrode and a lead for each of the other of said electrodes, and a resistance of more than ten megohms teaches in a connection between positive electrode and one of said supplementary electrodes. -10. An electronic device comprising an envelope and electrodes in said envelope, said device being characterized by the following relationship of; said electrodes: a negative electrode of tungsten. wire of about 0.002." diameter and substantially five-eighths I of an inch in lengthy'fla positive electrode of length and separated from each other about" one-eighth of an inch, a lead for each end of said negative electrode and a lead for each of the other of said electrodes.

11. An electronic device comprisinglan envelope and electrodes in said envelope, said device being characterized by the following relationship of said. electrodes: .A negative electrode of tungsten wire of about 0.002."

diameter and substantially five-eighths' of an inch in length, a positive electrode. of tungsten wire of about 0.005" in diameter and about one inch in length, said negative and positive electrodes being spaced apart five-thirty-seconds of an inch, a pair of supplementary electrodes of tungsten of about 0.005" diameter and about one inch in length, separated from each other about one eighth of an inch, and positioned one on each side of the path between the negative electrode and the positive electrode, all of said electrodes being mounted in parallel relation, a lead for each end of the negative electrode and a leadfor ach of the other of said electrodes.

In testimony whereofI hereto aflix my signature.

PETER COOPER HEWITT. 

